1#include "gba-serialize.h"
  2
  3#include "gba-audio.h"
  4#include "gba-io.h"
  5#include "gba-thread.h"
  6#include "gba-video.h"
  7
  8#include "util/memory.h"
  9#include "util/png-io.h"
 10#include "util/vfs.h"
 11
 12#include <fcntl.h>
 13#include <png.h>
 14#include <zlib.h>
 15
 16const uint32_t GBA_SAVESTATE_MAGIC = 0x01000000;
 17
 18void GBASerialize(struct GBA* gba, struct GBASerializedState* state) {
 19	state->versionMagic = GBA_SAVESTATE_MAGIC;
 20	state->biosChecksum = gba->biosChecksum;
 21	state->romCrc32 = gba->romCrc32;
 22
 23	state->id = ((struct GBACartridge*) gba->memory.rom)->id;
 24	memcpy(state->title, ((struct GBACartridge*) gba->memory.rom)->title, sizeof(state->title));
 25
 26	memcpy(state->cpu.gprs, gba->cpu->gprs, sizeof(state->cpu.gprs));
 27	state->cpu.cpsr = gba->cpu->cpsr;
 28	state->cpu.spsr = gba->cpu->spsr;
 29	state->cpu.cycles = gba->cpu->cycles;
 30	state->cpu.nextEvent = gba->cpu->nextEvent;
 31	memcpy(state->cpu.bankedRegisters, gba->cpu->bankedRegisters, 6 * 7 * sizeof(int32_t));
 32	memcpy(state->cpu.bankedSPSRs, gba->cpu->bankedSPSRs, 6 * sizeof(int32_t));
 33
 34	GBAMemorySerialize(&gba->memory, state);
 35	GBAIOSerialize(gba, state);
 36	GBAVideoSerialize(&gba->video, state);
 37	GBAAudioSerialize(&gba->audio, state);
 38}
 39
 40void GBADeserialize(struct GBA* gba, struct GBASerializedState* state) {
 41	if (state->versionMagic != GBA_SAVESTATE_MAGIC) {
 42		GBALog(gba, GBA_LOG_WARN, "Invalid or too new savestate");
 43		return;
 44	}
 45	if (state->biosChecksum != gba->biosChecksum) {
 46		GBALog(gba, GBA_LOG_WARN, "Savestate created using a different version of the BIOS");
 47		if (state->cpu.gprs[ARM_PC] < SIZE_BIOS && state->cpu.gprs[ARM_PC] >= 0x20) {
 48			return;
 49		}
 50	}
 51	if (state->id != ((struct GBACartridge*) gba->memory.rom)->id || memcmp(state->title, ((struct GBACartridge*) gba->memory.rom)->title, sizeof(state->title))) {
 52		GBALog(gba, GBA_LOG_WARN, "Savestate is for a different game");
 53		return;
 54	}
 55	if (state->romCrc32 != gba->romCrc32) {
 56		GBALog(gba, GBA_LOG_WARN, "Savestate is for a different version of the game");
 57	}
 58	memcpy(gba->cpu->gprs, state->cpu.gprs, sizeof(gba->cpu->gprs));
 59	gba->cpu->cpsr = state->cpu.cpsr;
 60	gba->cpu->spsr = state->cpu.spsr;
 61	gba->cpu->cycles = state->cpu.cycles;
 62	gba->cpu->nextEvent = state->cpu.nextEvent;
 63	memcpy(gba->cpu->bankedRegisters, state->cpu.bankedRegisters, 6 * 7 * sizeof(int32_t));
 64	memcpy(gba->cpu->bankedSPSRs, state->cpu.bankedSPSRs, 6 * sizeof(int32_t));
 65	gba->cpu->executionMode = gba->cpu->cpsr.t ? MODE_THUMB : MODE_ARM;
 66	gba->cpu->privilegeMode = gba->cpu->cpsr.priv;
 67	gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
 68
 69	GBAMemoryDeserialize(&gba->memory, state);
 70	GBAIODeserialize(gba, state);
 71	GBAVideoDeserialize(&gba->video, state);
 72	GBAAudioDeserialize(&gba->audio, state);
 73}
 74
 75static struct VFile* _getStateVf(struct GBA* gba, struct VDir* dir, int slot, bool write) {
 76	char path[PATH_MAX];
 77	path[PATH_MAX - 1] = '\0';
 78	struct VFile* vf;
 79	if (!dir) {
 80		snprintf(path, PATH_MAX - 1, "%s.ss%d", gba->activeFile, slot);
 81		vf = VFileOpen(path, write ? (O_CREAT | O_TRUNC | O_RDWR) : O_RDONLY);
 82	} else {
 83		snprintf(path, PATH_MAX - 1, "savestate.ss%d", slot);
 84		vf = dir->openFile(dir, path, write ? (O_CREAT | O_TRUNC | O_RDWR) : O_RDONLY);
 85	}
 86	return vf;
 87}
 88
 89static bool _savePNGState(struct GBA* gba, struct VFile* vf) {
 90	unsigned stride;
 91	void* pixels = 0;
 92	gba->video.renderer->getPixels(gba->video.renderer, &stride, &pixels);
 93	if (!pixels) {
 94		return false;
 95	}
 96
 97	struct GBASerializedState* state = GBAAllocateState();
 98	png_structp png = PNGWriteOpen(vf);
 99	png_infop info = PNGWriteHeader(png, VIDEO_HORIZONTAL_PIXELS, VIDEO_VERTICAL_PIXELS);
100	uLongf len = compressBound(sizeof(*state));
101	void* buffer = malloc(len);
102	if (state && png && info && buffer) {
103		GBASerialize(gba, state);
104		compress(buffer, &len, (const Bytef*) state, sizeof(*state));
105		PNGWritePixels(png, VIDEO_HORIZONTAL_PIXELS, VIDEO_VERTICAL_PIXELS, stride, pixels);
106		PNGWriteCustomChunk(png, "gbAs", len, buffer);
107	}
108	PNGWriteClose(png, info);
109	free(buffer);
110	GBADeallocateState(state);
111	return state && png && info && buffer;
112}
113
114static int _loadPNGChunkHandler(png_structp png, png_unknown_chunkp chunk) {
115	if (strcmp((const char*) chunk->name, "gbAs") != 0) {
116		return 0;
117	}
118	struct GBASerializedState state;
119	uLongf len = sizeof(state);
120	uncompress((Bytef*) &state, &len, chunk->data, chunk->size);
121	GBADeserialize(png_get_user_chunk_ptr(png), &state);
122	return 1;
123}
124
125static bool _loadPNGState(struct GBA* gba, struct VFile* vf) {
126	png_structp png = PNGReadOpen(vf, PNG_HEADER_BYTES);
127	png_infop info = png_create_info_struct(png);
128	png_infop end = png_create_info_struct(png);
129	if (!png || !info || !end) {
130		PNGReadClose(png, info, end);
131		return false;
132	}
133	PNGInstallChunkHandler(png, gba, _loadPNGChunkHandler, "gbAs");
134	PNGReadHeader(png, info);
135	PNGIgnorePixels(png, info);
136	PNGReadFooter(png, end);
137	PNGReadClose(png, info, end);
138	return true;
139}
140
141bool GBASaveState(struct GBA* gba, struct VDir* dir, int slot, bool screenshot) {
142	struct VFile* vf = _getStateVf(gba, dir, slot, true);
143	if (!vf) {
144		return false;
145	}
146	bool success = true;
147	if (!screenshot) {
148		vf->truncate(vf, sizeof(struct GBASerializedState));
149		struct GBASerializedState* state = vf->map(vf, sizeof(struct GBASerializedState), MAP_WRITE);
150		GBASerialize(gba, state);
151		vf->unmap(vf, state, sizeof(struct GBASerializedState));
152	} else {
153		_savePNGState(gba, vf);
154	}
155	vf->close(vf);
156	return success;
157}
158
159bool GBALoadState(struct GBA* gba, struct VDir* dir, int slot) {
160	struct VFile* vf = _getStateVf(gba, dir, slot, false);
161	if (!vf) {
162		return false;
163	}
164	if (!isPNG(vf)) {
165		struct GBASerializedState* state = vf->map(vf, sizeof(struct GBASerializedState), MAP_READ);
166		GBADeserialize(gba, state);
167		vf->unmap(vf, state, sizeof(struct GBASerializedState));
168	} else {
169		_loadPNGState(gba, vf);
170	}
171	vf->close(vf);
172	return true;
173}
174
175struct GBASerializedState* GBAAllocateState(void) {
176	return anonymousMemoryMap(sizeof(struct GBASerializedState));
177}
178
179void GBADeallocateState(struct GBASerializedState* state) {
180	mappedMemoryFree(state, sizeof(struct GBASerializedState));
181}
182
183void GBARecordFrame(struct GBAThread* thread) {
184	int offset = thread->rewindBufferWriteOffset;
185	struct GBASerializedState* state = thread->rewindBuffer[offset];
186	if (!state) {
187		state = GBAAllocateState();
188		thread->rewindBuffer[offset] = state;
189	}
190	GBASerialize(thread->gba, state);
191	thread->rewindBufferSize = thread->rewindBufferSize == thread->rewindBufferCapacity ? thread->rewindBufferCapacity : thread->rewindBufferSize + 1;
192	thread->rewindBufferWriteOffset = (offset + 1) % thread->rewindBufferCapacity;
193}
194
195void GBARewind(struct GBAThread* thread, int nStates) {
196	if (nStates > thread->rewindBufferSize || nStates < 0) {
197		nStates = thread->rewindBufferSize;
198	}
199	if (nStates == 0) {
200		return;
201	}
202	int offset = thread->rewindBufferWriteOffset - nStates;
203	if (offset < 0) {
204		offset += thread->rewindBufferSize;
205	}
206	struct GBASerializedState* state = thread->rewindBuffer[offset];
207	if (!state) {
208		return;
209	}
210	thread->rewindBufferSize -= nStates;
211	thread->rewindBufferWriteOffset = (offset + thread->rewindBufferCapacity - nStates) % thread->rewindBufferCapacity;
212	GBADeserialize(thread->gba, state);
213}